JPS5817706A - Antenna device - Google Patents

Abstract

PURPOSE:To accurately obtain the direction of antenna radiation by ratating a primary feeding horn of a mirror surface antenna mounted on a satellite around its fitting axis and measuring the strength of electric field at least for three points on ground. CONSTITUTION:A primary power feeding horn 12 of a circular symmetrical parabola antenna 11 mounted on a satellite 10 is placed on a focus of the antenna 11. A device 13 moves the horn 12 by a minute distance d1 and the horn 12 is rotated with a device 14 in the radius. In this case, at observing points (a), (b) and (c) on ground, the strength of electric field of a radiation pattern beam- shifted due to the movement of the horn 12 by the distance d1 is measured. Next, the horn 12 is further moved by a distance d1 and similar measurement is performed. This operation is repeated by N times. Taking distances corresponding to respective measuring ponts as da, db, dc, beam shift angles thetaa, thetab, thetac corresponding to the points can be obtained. Next, by drawing circles with thetaa-thetac in shift angles with the measuring points (a-c) as the center, the point where the three circles meet is the center of direction when the horn 12 is located at the focus.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an antenna device for measuring the directivity of antenna radiation directivity, and more particularly to a method for scanning a primary feeding horn of a mirror antenna.

As an example of a conventional method for determining the pointing direction, a method for determining the radiation pointing direction of four anti-j mounted on a geostationary satellite will be described.

As shown in Fig. 1, K uses a fixed station 4t on the ground or a 111m antenna to determine the radiation direction of the antenna 2 mounted on the geostationary satellite Jil above the ground surface 3. The electric field strength is measured at the vehicle-mounted station (mobile station) 5. Based on the ground measurement results, the radiation direction of the antenna is estimated.

The above electric field strength measurement has the following problems. Since it is not possible to measure the electric field strength at all measurement points within a short period of time, the measurement is carried out over a long period of time.

As a result, the radiation directional direction cannot be accurately determined because the measurement results include fluctuations in the transmission system on the satellite, fluctuations in the propagation path at each measurement time, and influences such as weather, etc. do not have.゛The present invention has been made in view of the above points.
The secondary power supply horn is rotated around its axis, and the electric field value is measured at at least three points on the ground. From the measurement results, the radiation directivity direction of the antenna can be accurately determined.

Ru. This antenna device is provided.

This constant method can be performed in a short time and does not require conventional injection bottles.

Hereinafter, the present invention will be explained in detail with reference to Examples.

FIG. 2 shows one embodiment of the present invention. Circular symmetrical parabolic antenna 11. A primary feeding horn 12 made of a waveguide; a device 13 for moving the feeding horn in a direction perpendicular to the axis of rotational symmetry; and a device 1 for rotating the feeding horn in a circular shape around the axis of rotational symmetry.
4. and observation point 15 on the ground surface (a), (b),
It is established from (C).

A specific configuration of an embodiment of the present invention is shown in FIG.

In Fig. 3 (1), if the primary feeding horn is placed at the focal point of the circular symmetrical parabolic antenna, the antenna radiation pattern will be the solid line shown in Fig. 3 (1). Next, Fig. 3 (1)
As shown in K, the primary feeding horn is moved from the focal point position to the nine directions perpendicular to the rotation center axis of the parabolic antenna.
A! 21, the beam is shifted by an angle of 0° compared to the solid line antenna radiation pattern shown in FIG.

This horn movement is 1i111d and the beam shift angle is 0.
There is a KFil-to-one correspondence between .

Therefore, the primary feeding horn is placed in focus, and then, as shown in FIG. 4, the device mouth is moved by a minute distance d1, and the device 14 rotates the ho/12 at that radius.

At this time, at points m, b, and c on the ground, the electric field strength of the beam-shifted radiation pattern caused by moving the primary feeding horn 12 by distance d and K is measured.

Next, move the primary horn further to a distance dt! However, rotate the horn by that radius and measure the electric field of the radiation pattern further beam-shifted at a, b, and c as before.

Repeat this N times.

In this measurement, if the primary horn moving distance d1 is set to a minute interval, there is always a state in which the observed electric field tetanization is maximum at measurement points a, b, and c. At this time, the beam center is directed to the measurement point.

The primary horn movement distance at that time can be determined. If the distance corresponding to each measurement point is 'a e db * dg, then the corresponding nine bee shift amount - a e 'b *
'c is required.

Fig.5 If you draw a circle with a shift angle 'ae'be-6, there will always be measurement points a, b, and c on this circle.

Therefore, as shown in Figure 5 (&0), if you draw a circle with -a-e'b*θ centered on heat eb, c, the point where the three circles intersect will be the point where one horn is at the focal point. Look at the orientation center t at nine o'clock.

゛ Compared to conventional measurement methods, the present invention can perform measurements in a shorter period of time, so fluctuations in the transmission system, which were disadvantages of conventional methods, and fluctuations in the propagation path and losses at each measurement time are not introduced. Therefore, it is impossible to accurately determine the radiation direction! Wear.

If the number of measurement points is increased to four or more, the accuracy will further increase.

Although a circularly symmetrical parabolic antenna is used in the embodiment of the present invention, it does not necessarily have to be circularly symmetrical, and the same effect can be obtained with a mirror antenna other than the I2BO2 antenna.

[Brief explanation of drawings]

Figure 1 shows the conventional measurement method, Figure 2 shows the actual measurement method,
FIGS. 3 and 4 are diagrams showing an example of the wing, and FIGS. 3 and 4 are diagrams showing a specific example of the present invention. The pit s diagram is a diagram showing a method for determining the pointing center. 1...Satellite, 2...Antenna, 3.
...Ground surface, 4...Fixed station, 5...
・Mobile station, 10... Satellite, 11... Antenna, Cap... Primary horn, 13... Device for moving the primary horn in a circular direction with its mounting perpendicular to the axis, 14 ... device for rotating the primary horn around the focal point, 15... ground plane, to... focal point, 21
...The point where the primary horn is moved by a distance d1. Agent Patent attorney Kensuke Norichika (and other names) Figure 1 τ1 Figure 2 Figure 8 (MuJ (L) θ=ρ θ Figure 4 Figure 5

Claims (1)

[Claims] The mirror antenna such as a parabolic antenna and the primary feeding horn of the antenna are attached in a direction perpendicular to the axis.
It is characterized by comprising a device for moving the secondary power supply horn and a device for rotating the enclosure of the shaft in a circular shape, and configured to have at least three or more electric field strength measurement points. antenna device.